1. Field of the Invention
The present general inventive concept relates to an apparatus and a method thereof to measure an amount of toner consumed in a printing system which includes an image forming apparatus, and more particularly, to an apparatus and a method thereof to measure toner consumption in a printing system, which is capable of measuring the toner consumption by applying different weights in accordance with the varying operation mode and image pattern of the printing system.
2. Description of the Related Art
FIG. 1 shows a general structure of a conventional printing system 1. As shown, the conventional printing system 1 mainly comprises a laser beam printer 10 and a computer 12.
The laser beam printer 10 is used in connection with the computer 12 via a communication interface 70.
The computer 12 transmits data to the laser beam printer 10 via the communication interface 70, and the printer 10 processes the received data for corresponding printing operations.
The printer 10 usually comprises the communication interface 70 constituting a connection between the computer 12 and the printer 10 for data transmission and reception, a program memory 20 storing therein a variety of control programs for the execution of the printer functions, a data memory 30 for storing a variety of data as they are generated in accordance with the execution of the control programs, a controller 13 for controlling respective parts of the printer 10 by executing the control programs, a printer engine 60 for driving printer mechanism under control of the controller 13, an operation panel 40 for the input of user command or selection, and a display 14 for displaying status of the printer.
In the printing system 1 as described above, toner consumption can be measured by installing a toner sensor (not shown) having light emitting and receiving elements in a toner cartridge (not shown), and notifying to the user of a sensed toner consumption as necessary. However, this approach requires a toner sensor and detection circuit, which subsequently increases a manufacturing cost of the printer.
Another way of measuring toner consumption is by counting the pages of printed paper since the mounting of a new toner cartridge. It is determined that the toner is exhausted when the counted number of printed pages exceeds a certain predetermined limit, and the user is notified of the same. For example, if a toner supplier guarantees 5000 pages of printing on the A4 sheets with a single toner cartridge, it can be presumed that the toner would be used up when the printed pages exceed 5000 pages.
However, the second approach has a shortcoming of inaccurate reference for determining toner exhaustion. That is, the toner suppliers estimate the printable pages with one toner cartridge generally based on the assumption that approximately 4% to 5% of the paper area requires the toner attachment. However, when considering the fact that the printing images usually vary among solid patterns such as black dots, character patterns such as lines and text, or halftone patterns such as graphs and drawings, the toner may be used up well before the printed pages reach the estimated printable pages, or a sufficient amount of toner may still be left even after the pages exceed the estimation.
Because it cannot be confirmed for sure that every page of the printing requires toner fixation for 4% to 5% of its area, accurate measurement of toner consumption cannot be guaranteed.
In order to resolve the problems mentioned above, another approach suggests to count the number of pixels of printing data synchronized to the video clock, and multiply the coefficients of toner consumption per pixel unit according to the counted pixels.
However, because this approach calculates toner consumption only based on the number of pixels of the counted printing data, by the Fringe effect, it cannot reflect the variations in toner consumption mainly according to varying modes of the operation such as print mode and a copy mode, and image patterns such as a solid pattern, a character pattern and a halftone pattern. Therefore, accurate toner consumption measurement cannot be guaranteed.
For example, according to the experiment conducted by the present applicant, toner consumption per pixel varies, depending on the operation mode and image pattern in use. The results of the experiment are listed in the table 1 below. As shown, toner consumption is the largest in the halftone pattern in the print mode, while the largest amount of toner is consumed in the solid pattern in the photo mode which is the sub operation mode of the copy mode.
TABLE 15% character5%5% solid patternpatternhalftone patternPrint mode1.37 × 10−08 g1.34 × 10−08 g1.43 × 10−08 gPhoto copy mode2.34 × 10−08 g1.92 × 10−08 g1.44 × 10−08 g
In order to overcome the shortcomings of the third approach, a suggestion has been made to calculate a laser diode turn-on ratio by counting the frequency of a laser beam emitted from a laser diode per a certain unit of pixel during the multiplication of the number of pixels of the counted printing data by the consumption coefficient, and use the calculated laser diode turn-on ratio as a compensate coefficient.
However, this fourth suggestion requires software programs for the data processing in frequency reading, which subsequently increases the program loads. Also, it has the possibility of errors in the software.
Furthermore, in the photo mode, which is the sub operation mode of the copy mode, the laser diode turn-on ratio is usually perceived to be similar between the solid pattern and the halftone pattern when the document is processed into data, and therefore, toner consumption can be measured to be similar. Therefore, the fourth approach also has a limit in accurately reflecting the difference of actual toner consumption between the solid pattern and the halftone pattern as indicated in the table 1.